Enhancement of PVDF membranes using graphene oxide nanoparticles and polyvinyl alcohol for water purification applications

Water contamination by heavy metal ions poses a significant environmental and public health challenge, necessitating the development of advanced and efficient treatment technologies. This study explores the advanced modification of thin-film composite (TFC) polyvinylidene fluoride (PVDF) membranes through cross-linking with glutaraldehyde (GA) and surface functionalization via a graphene oxide Nanoparticles (GONPs)/polyvinyl alcohol (PVA) coating using a dip-coating technique. The incorporation of GA as a cross-linking agent significantly enhanced the chemical and thermal stability of the thin-film coating, while the addition of GONPs improved the membrane's hydrophilicity and metal ion rejection efficiency. The mechanical strength of the modified membranes exhibited a notable increase, with the tensile strength rising from 3.58 MPa to 6.15 MPa as the PVA/GONPs loading increased. The performance of the functionalized membranes in removing Mn²⁺ and Fe²⁺ ions as the main contaminants was systematically evaluated under varying GONPs loadings. Results demonstrated that for an initial metal ion concentration of 100 ppm, the modified PVDF membranes achieved a removal efficiency of 95.5% for Mn²⁺ and 94.6% for Fe²⁺ in the first filtration cycle. Even after five successive filtration cycles, removal rates remained above 60%, highlighting the membranes' durability and sustained performance. This study presents a promising strategy for enhancing polymeric membranes, offering an efficient and scalable solution for heavy metal removal in wastewater treatment applications.